Electric Motor Rotor End Plate Axial Load Distribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing rotors for electric rotating machines face challenges with axial spreading and stress concentration at the end plates, leading to reduced durability and impact resistance due to deflection stress concentration and impact load concentration at specific spots.
Innovation Solution
The rotor design incorporates end plates with through-holes and an intermediate bent portion that distribute axial loads to prevent axial spreading, reducing deflection stress concentration by inducing stress mainly around the through-holes and bent portions, thereby enhancing durability and impact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the thickness of the end plate is increased at the radially outer end portion to prevent rotor core spreading, then the rotor core spreading is prevented, but deflection stress concentration occurs at the radially inner end portion of the end plate
Solution Approach 1:
The end plate is designed with non-uniform thickness distribution, being thicker at the radially outer end portion and thinner at the radially inner end portion. This local quality variation allows the thick portion to prevent rotor core spreading while the thin portion reduces deflection stress concentration, resolving the contradiction between stability and stress distribution.
Solution Approach 2:
The invention introduces a radial dimension variation in end plate thickness to solve the axial spreading problem. By varying thickness in the radial direction rather than uniformly increasing axial thickness, the solution prevents spreading while avoiding stress concentration at the inner end portion.
2Stability of the object's composition
If the end plate is deflected to enable the radially outer end portion to press the rotor core axially inward, then the rotor core spreading is prevented, but stress concentration occurs at the radially inner end portion where impact loads are applied
Solution Approach 1:
The end plate features local quality variation with different thicknesses at different radial positions. The thinner radially inner end portion has reduced stiffness, allowing it to flex under impact loads without concentrating stress, thereby improving impact resistance while the thicker outer portion maintains spreading prevention.
Solution Approach 2:
The invention converts the potential harm of impact loads applied at the radially inner end portion into a beneficial effect. By designing this region with reduced thickness, impact loads cause controlled flexing rather than stress concentration, transforming a weakness into a stress-relief mechanism that enhances overall reliability.
3Stability of the object's composition
If both deflection stress concentration and impact load concentration occur at the same spots of the end plates, then the end plates experience combined stress, but it becomes difficult to secure high durability and high impact resistance
Solution Approach 1:
The end plate is designed with spatially varying thickness to separate stress concentration zones from impact load zones. The radially inner end portion is made thinner to avoid combined stress concentration, while the radially outer portion maintains sufficient thickness for structural integrity, thereby achieving both durability and impact resistance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively reduces total stress at the non-stator-side end portions, improving both durability and impact resistance of the end plates while simplifying the manufacturing process by eliminating the need for machining and reducing manufacturing costs.
Implementation Method 1
exerts an axial load on the corresponding axial end face of the rotor core by an elastic force of the end plate
Data Source
AI summary
A rotor includes a rotor core comprised of magnetic steel sheets laminated in the axial direction and a pair of end plates that are respectively provided on the axial end faces of the rotor core so as to together sandwich the rotor core in the axial direction. The rotor is rotatably disposed in an electric rotating machine with a circumferential surface of the rotor core facing a stator. At least one of the end plates is configured to have through-holes, each of which is formed so as to axially penetrate the end plate, and a pressing portion that is radially positioned on the stator side of the through-holes. The pressing portion abuts a corresponding one of the axial end faces of the rotor core and exerts an axial load on the corresponding axial end face of the rotor core by an elastic force of the end plate.